Blow molded article with retaining feature and method of creating same

ABSTRACT

A blow molded article includes an outer wall and an article retaining feature projecting outwardly therefrom. The article retaining feature includes a distal wall and a side wall connecting the distal wall and the outer wall of the blow molded article. The side wall is generally orthogonal to the outer wall of the blow molded article, and an inner surface is defined at least partially by inner edges of the side wall, the distal wall and the outer wall of the blow molded article. The side wall has a hole integrally molded therein.

RELATED APPLICATIONS

This patent application claims the benefit of, under Title 35, UnitedStates Code, Section 119(e), U.S. Provisional Patent Application No.60/351,333, filed Nov. 13, 2001 and U.S. Provisional Patent ApplicationNo. 60/335,386, filed Nov. 15, 2001.

FIELD OF THE INVENTION

The present invention relates to an improved retaining feature which canbe incorporated into a double wall blow molded article to retainaccessories, such as handles, on the article and a method of molding anarticle having such a retaining feature.

BACKGROUND OF THE INVENTION

Double wall blow molded articles, such as carrying cases, have beenknown for decades. Such articles provide a useful combination ofdesirable properties, such as having high strength and relatively lightweight, at a modest cost. It has also long been known to provideretaining features in or on such double wall blow molded articles inorder to retain accessories, such as handles or the like, on or in thearticle. However, while the art of blow molded articles, including blowmolded articles provided with retaining features, is well developed,deficiencies still exist.

One of such deficiencies relates to the manner in which accessorieswhich are not an integral part of the blow molded article are retainedthereby. While numerous such retaining features are known, they sufferfrom a number of disadvantages, such as being complex, and thereforeexpensive to produce and/or difficult to mold, and/or not being strongenough to support the blow molded article (particularly when the blowmolded article comprises a case in which heavy objects are carried).

Another deficiency of known retaining features relates to the method inwhich they are created. Typically, retaining features for accessorieswhich are not an integral part of the blow molded article require thatvarious secondary operations be performed after the article is blowmolded. Examples of such secondary operations include drilling,punching, etc. A disadvantage of requiring such secondary features isthat they add to the complexity and cost of manufacturing theblow-molded article.

What is desired, therefore, is a blow molded article which includes aretaining feature which is simple and inexpensive to produce, whichprovides a relatively high strength connection between the blow moldedarticle and the accessory, such as a handle, and which is formed duringthe molding process, without the need for secondary operations.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a blowmolded article which includes a retaining feature which is simple andinexpensive to produce.

Another object of the present invention is to provide a blow moldedarticle which includes a retaining feature having the abovecharacteristics and which provides a relatively high strength connectionbetween the blow molded article and the accessory, such as a handle.

A further object of the present invention is to provide a blow moldedarticle which includes a retaining feature having the abovecharacteristics and which is formed during the molding process, withoutthe need for secondary operations.

These and other objects of the present invention are achieved byprovision of a blow molded article comprising an outer wall and anarticle retaining feature projecting outwardly therefrom. The articleretaining feature includes a distal wall and a side wall connecting thedistal wall and the outer wall of the blow molded article. The side wallis generally orthogonal to the outer wall of the blow molded article,and an inner surface is defined at least partially by inner edges of theside wall, the distal wall and the outer wall of the blow moldedarticle. The side wall has a hole integrally molded therein.

Preferably, the article retaining feature projects outwardly andupwardly from a top surface of the outer wall of the blow moldedarticle. The hole in the side wall is preferably located proximate tothe distal wall, and most preferably adjacent to the inner surface suchthat a thin bridge of material connects the distal wall and the outerwall of the blow molded article. In one embodiment, the articleretaining feature comprises two generally parallel and spaced apart sidewalls, each having a hole therein, and a handle having a longitudinalcenter portion and a leg portion protecting from each end thereof isprovided. Each of the leg portions includes a pin projecting inwardlytherefrom, with each of the pins of the handle being received in thehole in each of the side walls.

In another respect, the present invention is directed to a method ofcreating a blow molded article having a retaining feature. A first moldhalf is provided having a protrusion extending from an inner surfacethereof, the protrusion having a protuberance extending therefrom in adirection generally parallel to the inner surface, the protuberancehaving a generally planar face and being spaced apart from the innersurface so as to define a space therebetween. A second mold half is alsoprovided having a generally planar side wall generally parallel to thegenerally planar face of the protuberance. The first mold half and thesecond mold half are brought together with a molten parison disposedtherebetween such that the generally planar face of the protuberance ofthe first mold half abuts the generally planar side wall of the secondmold half and such that the parison flows into a cavity defined by thespace between the protuberance and the inner surface of the first moldhalf and the generally planar side wall of the second mold half in orderto form a wall having an integrally molded hole separated from an edgethereof by a thin bridge of material.

Preferably, the molten parison is allowed to at least partially solidifyand the at least partially solidified parison is removed from the moldby elastically deforming the bridge of material around the protuberance.The first mold half may include two protrusions, each having aprotuberance facing in opposite directions and the second mold half mayinclude two generally planar side walls such that two walls are formed,each having an integrally molded hole separated from an edge thereof bya thin bridge of material. When such is the case, the method may furthercomprise the steps of providing a handle having a longitudinal centerportion and a leg portion protecting from each end thereof, each of theleg portions having a pin projecting inwardly therefrom, and insertingeach of the pins of the handle into one of the holes.

In another respect, the present invention is directed to a mold forcreating a blow molded article having a retaining feature. The mold mayinclude a first mold half having a protrusion extending from an innersurface thereof, the protrusion having a protuberance extendingtherefrom in a direction generally parallel to the inner surface, theprotuberance having a generally planar face and being spaced apart fromthe inner surface so as to define a space therebetween. A second moldhalf includes a generally planar side wall generally parallel to thegenerally planar face of the protuberance. When the first mold half andthe second mold half are brought together with a molten parison disposedtherebetween, the generally planar face of the protuberance of the firstmold half abuts the generally planar side wall of the second mold halfsuch that the parison flows into a cavity defined by the space betweenthe protuberance and the inner surface of the first mold half and thegenerally planar side wall of the second mold half in order to form awall having an integrally molded hole separated from an edge thereof bya thin bridge of material.

In one embodiment the first mold half includes two protrusions, eachhaving a protuberance facing in opposite directions, and the second moldhalf includes two generally planar side walls. When such is the case,when the first mold half and the second mold half are brought togetherwith a molten parison disposed therebetween two walls are formed, eachhaving an integrally molded hole separated from an edge thereof by athin bridge of material.

The invention and its particular features and advantages will becomemore apparent from the following detailed description considered withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric side view of an embodiment of a blow moldedarticle which includes a retaining feature in accordance with thepresent invention;

FIG. 2 is an enlarged side plan view of the blow molded article whichincludes a retaining feature of FIG. 1;

FIG. 3 is a partially cross-sectional view illustrating an embodiment ofa molding process used to create the blow molded article which includesa retaining feature of FIG. 1 shown with the mold in an open position;and,

FIG. 4 is a partially cross-sectional view illustrating the moldingprocess of FIG. 3 shown with the mold in a closed position.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

Referring first to FIGS. 1 and 2, a blow molded article 10 having anouter wall 12 and an article retaining feature 14 projecting outwardlytherefrom in accordance with one embodiment of the invention is shown.Blow molded article 10 may comprise any of a number of articles such astool boxes, carrying cases for various articles, etc. In the Figures,blow molded article 10 comprises a carrying case with article retainingfeature 14 projecting from a top surface thereof. However, it should beunderstood that article retaining feature 14 could project outwardlyfrom a lower surface and/or side surfaces of blow molded article 10instead of or in addition to projecting from the top surface thereof. Itshould also be understood that when directional references, such as“top,” “bottom,” “upper,” “lower,” “side,” etc., are made herein suchreferences are directed to the orientation shown in the Figures.However, it is expressly contemplated that the orientation of blowmolded article 10 could be varied and is not limited to the orientationshown in the Figures.

Article retaining feature 14 includes a distal wall 16 and two sidewalls 18 connecting distal wall 16 and outer wall 12 of blow moldedarticle 10. Side walls 18 are generally parallel and are generallyorthogonal to outer wall 12 and distal wall 16. An inner surface 20 isdefined at least partially by inner edges of side walls 18, distal wall16 and outer wall 12.

Each of side walls 18 has a hole 22 integrally molded therein, asdescribed more fully below. A handle 24 having a longitudinal centerportion 26 and a leg portion 28 protecting from each end thereof isprovided. Each of leg portions 28 includes a pin 30 projecting inwardlytherefrom, with each of pins 30 of the handle being received in hole 22in each of side walls 18. Side walls 18 are spaced apart a distancesmaller than the distance separating leg portions 28 of handle 24, butgreater than the distance separating the inner most extents of pins 30of handle 24. As will be understood by those skilled in the art, handle24 can thus be installed on retaining feature 14 by elasticallystretching leg portions 28 apart, positioning pins 30 proximate to holes22, and then allowing leg portions 28 to return to their originalpositions with pins 30 retained in holes 22.

Holes 22 are preferably located proximate to distal wall 16. This isdesirable so that the weight of article 10 on handle 24 is not bornesolely by holes 22. Rather, as best seen in FIG. 2, by locating holes 22proximate to distal wall 16, pins 30 can abut distal wall 16, therebyallowing distal wall 16 to bear at least some of the weight of article10 on handle 24.

It is also preferable that holes 22 be located adjacent to inner surface20 such that a relatively thin bridge of material 32 connects distalwall 16 and outer wall 12. This is desirable to facilitate removal ofblow molded article 10 from the mold during manufacture, as if a thickerportion of material separated hole 22 and inner surface 20, it may bedifficult to remove blow molded article 10 from the mold, as more fullydescribed below.

Referring now to FIGS. 3 and 4 a method of creating blow molded article10 and molds used to create blow molded article 10 are shown. A firstmold half 100 is provided having a protrusion 102 extending from aninner surface 104 thereof. Protrusion 102 has a protuberance 106extending therefrom in a direction generally parallel to inner surface104. Protuberance 106 has a generally planar face 108 and is spacedapart from inner surface 104 so as to define a space 110 therebetween. Asecond mold half 112 is also provided having a generally planar sidewall 114 generally parallel to generally planar face 108 of protuberance106.

First mold half 100 and second mold half 112 are brought together with amolten parison 116 disposed therebetween such that generally planar face108 of protuberance 106 of first mold half 100 abuts generally planarside wall 114 of second mold half 112 (best seen in FIG. 4). As firstmold half 100 and second mold half 112 are brought together to theclosed position shown in FIG. 4, parison 116 flows into a cavity 118defined by space 110 between protuberance 106 and inner surface 104 offirst mold half 100 and generally planar side wall 114 of second moldhalf 112 in order to form side wall 18 having integrally molded hole 22separated from an edge thereof by a thin bridge of material 32 (shown inFIGS. 1 and 2). Because generally planar face 108 of protuberance 106 offirst mold half 100 abuts generally planar side wall 114 of second moldhalf 112, the molten parison 116 in that area is compressed out of thearea such that no parison (or only an extremely thin layer of theparison) remains in this area, thereby creating a hole.

Air or some other pressurized fluid may then be introduced into parison116 in order to cause parison 116 to conform to the shape of the mold100, 112 as is known in the art. Preferably, molten parison 116 isallowed to at least partially solidify before being removed from themold by elastically deforming bridge of material 32 around protuberance106.

When article retaining feature 14 is used to retain a handle 24, it isdesirable for article retaining feature 14 to include two generallyparallel side walls 18 each having a hole 22 integrally molded therein.When such is the case, first mold half 100 may include two protrusions102 (arranged essentially in a mirror image to the one shown in FIGS. 3and 4), each having a protuberance 106 facing in opposite directions andthe second mold half 112 may include two generally planar side walls 114such that two walls 18 are formed, each having an integrally molded hole22 separated from an edge thereof by a thin bridge of material 32.

When such is the case, a handle 24 as described above may be provided.Handle 24 may be installed by inserting each of pins 30 of handle 24into one of holes 22.

The present invention, therefore, provides a blow molded article whichincludes a retaining feature which is simple and inexpensive to produce,which provides a relatively high strength connection between the blowmolded article and the accessory, such as a handle, and which is formedduring the molding process, without the need for secondary operations.

Although the invention has been described with reference to a particulararrangement of parts, features and the like, these are not intended toexhaust all possible arrangements or features, and indeed many othermodifications and variations will be ascertainable to those of skill inthe art.

1. A blow molded article comprising an outer wall and an articleretaining feature projecting outwardly therefrom; said article retainingfeature adapted to receive a handle having a longitudinal center portionand a leg portion projecting from each end thereof, each of the legportions having a pin projecting therefrom, each pin defining a free endspaced apart from a free end defined by each other pin, and said articleretaining feature comprising: a distal wall; a side wall connecting saiddistal wall and the outer wall of the blow molded article, said sidewall being generally orthogonal to the outer wall of the blow moldedarticle; an inner surface defined at least partially by inner edges ofsaid side wall, said distal wall and the outer wall of the blow moldedarticle; wherein said side wall has a hole integrally molded therein;and wherein the hole in each of said side walls has a closed peripherydefined by a bridge of material connecting said distal wall and saidouter wall adjacent said inner surface, and is located proximate to saiddistal wall such that the free ends defined by the pins of said handlebear directly against said distal wall.
 2. The blow molded article ofclaim 1 wherein said article retaining feature projects outwardly andupwardly from a top surface of the outer wall of the blow moldedarticle.
 3. The blow molded article of claim 1 wherein the hole in saidside wall is located proximate to said distal wall.
 4. The blow moldedarticle of claim 1 wherein the hole in said side wall is locatedadjacent to said inner surface such that a thin bridge of materialconnects said distal wall and the outer wall of the blow molded article.5. The blow molded article of claim 1 wherein said article retainingfeature comprises two generally parallel and spaced apart side walls. 6.A blow molded article comprising; a outer wall: a distal wall; twospaced apart and generally parallel side walls connecting said distalwall and said outer wall, said side walls being generally orthogonal tosaid outer wall; an inner surface defined at least partially by inneredges of said side walls, said distal wall and said outer wall; whereineach of said side walls has a hole integrally molded therein; a handlehaving a longitudinal center portion and a leg portion protecting fromeach end thereof, each of the leg portions having a pin projectingtherefrom, each pin defining a free end spaced apart from a free enddefined by each other pin; wherein each of the pins of said handle arereceived in the hole in each of said side walls; and wherein the hole ineach of said side walls has a closed periphery defined by a bridge ofmaterial connecting said distal wall and said outer wall adjacent saidinner surface, and is located proximate to said distal wall such thatthe free ends defined by the pins of said handle bear directly againstsaid distal wall.
 7. The blow molded article of claim 6 wherein saidouter wall comprises an outer top wall of the blow molded article. 8.The blow molded article of claim 6 wherein the hole in each of said sidewalls is located adjacent to said inner surface such that a thin bridgeof material connects said distal wall and said outer wall.